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Trial registered on ANZCTR


Registration number
ACTRN12614000559617
Ethics application status
Approved
Date submitted
19/05/2014
Date registered
26/05/2014
Date last updated
26/05/2014
Type of registration
Retrospectively registered

Titles & IDs
Public title
Does short compared to long ureteral stenting following pyeloplasty offer comparable periinterventional and functional outcomes?
Scientific title
Does a two weeks compared to a six weeks ureteral stent indwelling time following minimally invasive pyeloplasty in patients with uretero-pelvic-junction obstruction offer comparable periinterventional and functional outcomes?
Long term data from a prospective randomized trial
Secondary ID [1] 284485 0
Nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Uretero-pelvic junction obstruction 291748 0
Condition category
Condition code
Renal and Urogenital 292116 292116 0 0
Kidney disease

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
All patients underwent routine physical examination, total blood count, serum biochemistry, and urine analysis and culture prior to surgery. Preoperatively, baseline split kidney function (scintigraphy) was assessed. Additionally, surgery was planned based on either contrast enhanced CT-scan or intravenous urography.
Patients received 1.2g amoxicillin and clavulanic acid as perioperative prophylaxis. Routinely, retrograde examination with consecutive ureteral stent (DJ stent) insertion was performed immediately prior to pyeloplasty with the patients already under general anesthesia.
Focusing on the main surgical procedure (pyeloplasty), we apply a minimally invasive (pure laparoscopic or robotic assisted laparoscopic) transperitoneal approach using four trocars and the following steps: Initially, the colon is mobilized and reflected. Once the ureter is identified, it is chased to the renal pelvis in order to identify eventually crossing lower pole vessels. Thereafter the ureter is transected at its origin from the renal pelvis and the strictured proximal segment spatulated over 1,5cm. Routinely, the enlarged renal pelvis is reduced in size. With the help of three stay sutures, the uretero-pelvic anastomosis is sawn. Finally, the re-dimensioned pyelon is closed with a running suture and water tightness tested by i.v. Furosemide application. The anastomosis is covered with surrounding tissue/Gerota’s fascia and a drain routinely placed at the anastomosis. The drainage is typically removed if the drained volume is < 20ml/24 hours. The Foley catheter remains for 5 days.

In open surgery, ureteral stents were typically removed one week after pyeloplasty (Dobry E, Usai P, Studer UE, Danuser H. Is antegrade pyeloplasty really less invasive than open pyeloplasty? Urologia internationalis. 2007;79(2):152-6). However, nowadays, pyeloplasties are mainly performed through a minimally invasive approach. Fundamentally, DJ stent indwelling time is surgeon dependent and varies somewhere between 1 week and 2 months according to the available literature. While we used to keep the stents for 6 weeks after pyeloplasty in earlier days, this policy has changed over time to a shorter indwelling time around 2 weeks.

We therefore aimed to investigate the evantual impact of a short (group A: 2 weeks) compared to a long (group B: 6 weeks) DJ stent indwelling time.

DJ-stents were removed in the outpatient clinic after 2 (group A) and 6 weeks (group B), respectively.
Intervention code [1] 289256 0
Treatment: Surgery
Intervention code [2] 289425 0
Treatment: Devices
Comparator / control treatment
The study focused on the eventual impact of a short (group A: 2 weeks) compared to a long (group B: 6 weeks) DJ stent indwelling time. The surgical procedure as well as the immediate perioperative period were identical for both study groups. The only difference was DJ stent indwelling time.
Group B (6 weeks) is considered to be the control group.
Control group
Active

Outcomes
Primary outcome [1] 291996 0
Primary endpoint was functional success, defined as correction of obstruction.

The evaluation of functional outcome/success based on objective (intravenous urography (IVU) and renal scintigraphy) and subjective findings (flank pain). Success was defined as no obstruction in the IVU and undelayed and unobstructed drainage in the scintigraphy (T1/2 < 20 min), stable or improved split kidney function on the affected side and no residual flank pain.
Timepoint [1] 291996 0
IVU took place at 3 months and renal scintigraphies were performed at 6, 12 and 24 months. Subjective findings were simultaneously evaluated at these timepoints.

All patients were and will be followed for a total of 5 years. Our median follow up so far is 36 months. However, eventual failures (recurrent uretero-pelvic junction obstruction) following pyeloplasty are mainly expected to occur within the first year after surgery.
Secondary outcome [1] 307978 0
Perioperative outcome: Operative time
Timepoint [1] 307978 0
Operative time was defined as period from skin incision to skin closure, recorded by the anesthesiologist.
Secondary outcome [2] 308365 0
Perioperative outcome: Blood loss
Timepoint [2] 308365 0
Estimated and documented by the anesthesiologist at the end of the surgical procedure.
Secondary outcome [3] 308366 0
Perioperative outcome: Drainage time
Timepoint [3] 308366 0
Wound drains were removed once the drained volume was less than 20ml/24 hours. This was typcially between postoperative day 2 and 5. Drainage time was recorded within the patients digital chart.
Secondary outcome [4] 308367 0
Perioperative outcome: Length of hospital stay
Timepoint [4] 308367 0
The length of hospital stay ist automatically documented within the patients digital chart.
Secondary outcome [5] 308368 0
Stent related complications such as stent dislocation, urinary leakage and infection.
Timepoint [5] 308368 0
Eventual stent related complications were recorded during the entire stent indwelling time (2 respectively 6 weeks)
1.) Correct stent positioning was checked by ultrasound at the day of hospital discharge.
2.) The fluid drained through the wound drain was measured and documented. In case of a high output, further analyses were undertaken (creatinin estimation of the drained fluid)
3.) Urine analysis was performed at hospital entry, immediately before stent removal and inbetween if deemed necessary.

Eligibility
Key inclusion criteria
Patients diagnosed with urodynamic relevant uretero-pelvic junction obstruction
Informed consent
Minimum age
No limit
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Conversion to open surgical procedure
Missing follow up information

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Concealed allocation by computer.
After entering patients data in a central computer, the later assigned the subjects either to group A or group B. Patients were not further stratified.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomization program used was developed from an experienced external statistican together with our departemental computer specialist.
=> computerized sequence generation
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Phase 4
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis
Based on the published success rates following pyeloplasty ranging between 87% and 100%, a reference group (6 weeks) proportion of 0.99 and a treatment group (2 weeks) proportion of 0.92 under the null hypothesis of inferiority were assumed. A one-sided Z test (unpooled) with an offset = 0 was applied. Within this setting, a sample size of 41 patients in each group was calculated to detect a difference of 7% with significance level of 5% (alpha = 0.05) and power of 94% (beta = 0.06). Baseline comparisons are based on one-sided t-test (patients characteristics) and Chisquare test or one-sided Fisher’s exact test (categorical data). A linear regression model (patients characteristics) was used to identify predictors of postoperative function of the affected kidney.
Statistical analyses were performed by the Department of Mathematics and Statistics, University of Bern, Switzerland with StatXact v.8 statistical software (Cytel, Cambridge, MA, USA), PASS (NCSS) and SAS v9.1.

Recruitment
Recruitment status
Active, not recruiting
Date of first participant enrolment
Anticipated
1/05/2007
Actual
1/05/2007
Date of last participant enrolment
Anticipated
1/08/2013
Actual
1/08/2013
Date of last data collection
Anticipated
Actual
Sample size
Target
82
Accrual to date
Final
Recruitment outside Australia
Country [1] 6021 0
Switzerland
State/province [1] 6021 0
Berne

Funding & Sponsors
Funding source category [1] 289143 0
Hospital
Name [1] 289143 0
University Hospital Berne
Country [1] 289143 0
Switzerland
Primary sponsor type
University
Name
Department of Urology, University of Berne
Address
University Hospital of Berne
Inselspital
3010 Berne
Country
Switzerland
Secondary sponsor category [1] 287808 0
None
Name [1] 287808 0
Address [1] 287808 0
Country [1] 287808 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 291041 0
Ethical approval not required
Ethics committee address [1] 291041 0
Ethics committee country [1] 291041 0
Date submitted for ethics approval [1] 291041 0
Approval date [1] 291041 0
Ethics approval number [1] 291041 0

Summary
Brief summary
First described in 1993, laparoscopic pyeloplasty has largely replaced the open reconstructive procedure described by Anderson-Hynes. Mimicking the open approach, the minimally invasive technique offers equivalent success rates (87-100%) with minimal morbidity. The use of transanastomotic stents following pyeloplasty remains a debated issue. While nowadays some surgeons even promote a stentless procedure despite a relatively high prolonged urinary leakage risk and the need for secondary interventions, the majority of urologists still uses some sort of transanastomotic stents. However, there exists no consensus on optimal stent indwelling time which ranges somewhere between 1 week and 2 months. Furthermore, ureteric stents are not free of complications and side effects and therefore, stent indwelling time is an important issue. Until recently stents were typically removed at the surgeon’s discretion because there was no data on optimal stent indwelling time available.
Fortunately, there exists one recent prospective randomized trial suggesting that 1 week stenting is non inferior to 4 week stenting in terms of functional outcomes. However, this study lacks a rigid and long term follow up and therefore, the question of long-term safety/success after a short stenting time remains unanswered (One-week versus four-week stent placement following laparoscopic and robot assisted pyeloplasty - Results of a prospective randomized single-center study. Danuser H et al. BJU Int. 2014 Jan 28. doi: 10.1111/bju.12652.).

Similarly, our study aimed to investigate the impact of a short (2 weeks) compared to a long (6 weeks) ureteral stent indwelling time. In contrast to the above mentioned trial, we follow our patients meticulously over years including scintigraphies and are therefore able, to provide perioperative data as well as robust long term functional results. In addition, we aimed to identify patients factors predicting the postoperative function of the affected kidney.
Trial website
Trial related presentations / publications
Public notes
This data collection was part of an internal quality control at our hospital, comparing two worldwide clinically accepted, applied and established policies in terms of ureteral stent indwelling time following pyeloplasty.
As stated previously, the timepoint of ureteral stent removal following pyeloplasty bases mainly on the surgeons descretion and varies worldwide somewhere between 1 week and 8 weeks. Over the past decades, surgeons at our institution tended to remove the stents either after 2 weeks or 6 weeks. This internal quality control was performed in order to develop a solid institutional policy. Therefore, the study protocol has not been submitted to an ethics committee.

Contacts
Principal investigator
Name 47926 0
Dr Pascal Zehnder
Address 47926 0
Department of Urology
University Hospital of Berne
Inselspital
3010 Berne
Country 47926 0
Switzerland
Phone 47926 0
+41 316320797
Fax 47926 0
+41 316322181
Email 47926 0
[email protected]
Contact person for public queries
Name 47927 0
Pascal Zehnder
Address 47927 0
Department of Urology
University Hospital of Berne
Inselspital
3010 Berne
Country 47927 0
Switzerland
Phone 47927 0
+41 316320797
Fax 47927 0
+41 316322181
Email 47927 0
[email protected]
Contact person for scientific queries
Name 47928 0
Pascal Zehnder
Address 47928 0
Department of Urology
University Hospital of Berne
Inselspital
3010 Berne
Country 47928 0
Switzerland
Phone 47928 0
+41 316320797
Fax 47928 0
+41 316322181
Email 47928 0
[email protected]

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